Foraging Signals Promote Swarming in Starving Pseudomonas aeruginosa

Badal, Divakar; Jayarani, Abhijith Vimal; Kollaran, Mohammad Ameen; Prakash, Deep; Monisha, P; Singh, Varsha

doi:10.1128/mbio.02033-21

Cited by 22 publications

(19 citation statements)

References 49 publications

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“…Since rhamnolipid is essential for swarming in Pa (Caiazza et al, 2005), we predicted that iron supplementation would suppress rhamnolipid production and thus will suppress swarming. As shown in Figure S7, Pa swarms on M9 medium solidified with 0.6% agar as shown earlier (Badal et al, 2021; Kollaran et al, 2019). However, supplementation of M9 swarm agar plates with iron suppressed swarming in a dose-dependent manner (Figure S7).…”

Section: Resultssupporting

confidence: 73%

“…Still, we did not observe any clearance (Figure S1B), suggesting that the clearance of Kp is a specific function of Pa cells. The minimal media-specific behavior of Pa against Kp is reminiscent of the swarming motility of P. aeruginosa which is also greatly influenced by growth media (Badal et al, 2021; Kollaran et al, 2019). Altogether, our experiments indicate that some factor(s) in the M9 medium promotes action of Pa against Kp.…”

Section: Resultsmentioning

confidence: 99%

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Toroidal displacement of Klebsiella pneumoniae by Pseudomonas aeruginosa is a unique mechanism to avoid competition for iron

Pradhan

Tanwar

Parthasarathy

et al. 2022

Preprint

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Competition for resources is one of the major drivers for evolution and retention of new traits in microbial communities. Quorum-dependent traits of opportunistic human pathogen Pseudomonas aeruginosa allow it to survive and thrive in nature. Here, we report a unique surfactant-driven pushing mechanism that P. aeruginosa employs specifically against Klebsiella pneumoniae. The pushing is accomplished in a manner that is dependent on nutrient limitation and quorum sensing. We find that P. aeruginosa employs neither proteases nor toxic secondary metabolites against K. pneumoniae. Rhamnolipid biosurfactant appears to be the only factor required to displace Klebsiella effectively. Both rhamnolipid production and the pushing ability of P. aeruginosa are suppressed by iron supplementation. We show that both these bacteria produce several siderophores in minimal medium and rapidly deplete iron. Under these conditions, P. aeruginosa pushes Klebsiella away from the substratum using rhamnolipid, reducing the competition for iron. Our study describes a unique quorum and iron-responsive mechanism in P. aeruginosa to support its own growth during resource competition.

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Section: Resultssupporting

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Toroidal displacement of Klebsiella pneumoniae by Pseudomonas aeruginosa is a unique mechanism to avoid competition for iron

Pradhan

Tanwar

Parthasarathy

et al. 2022

Preprint

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“…Surprisingly, the growth deficit of the Δ erdR mutant on propionate was even more pronounced than that of a Δ acsA mutant. This indicates that additional downstream targets of ErdR, such as ErcS, ErbR or the ethanol oxidation system, may also be required for optimal propionate catabolism in Pa (54).…”

Section: Resultsmentioning

confidence: 99%

Systems-wide dissection of organic acid assimilation in Pseudomonas aeruginosa reveals a novel path to underground metabolism

Dolan

Wijaya

Kohlstedt

et al. 2022

Preprint

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The human pathogen Pseudomonas aeruginosa (Pa) is one of the most frequent and severe causes of nosocomial infection. This organism is also a major cause of airway infections in people with cystic fibrosis (CF). Pa is known to have a remarkable metabolic plasticity, allowing it to thrive in diverse environmental conditions and ecological niches, yet little is known about the central metabolic pathways which sustain its growth during infection, or precisely how these pathways operate. In this work, we used a combination of omics approaches (transcriptomics, proteomics, metabolomics and 13C-fluxomics) and reverse genetics to provide a systems-level insight into how the infection-relevant organic acids, succinate and propionate, are metabolized by Pa. Moreover, through structural and kinetic analysis of the 2-methylcitrate synthase (PrpC) and its paralogue, citrate synthase (GltA), we show how these two crucial enzymatic steps are interconnected in Pa organic acid assimilation. We found that Pa can rapidly adapt to the loss of GltA function by acquiring mutations in a transcriptional repressor, which then de-represses prpC expression. Our findings provide a clear example of how underground metabolism, facilitated by enzyme substrate promiscuity, rewires Pa metabolism, allowing it to overcome the loss of a crucial enzyme. This pathogen-specific knowledge is critical for the advancement of a model-driven framework to target bacterial central metabolism.

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“…As previously stated, the rhl system controls rhamnolipid synthesis, which is crucial for biofilm development and maintenance in P. aeruginosa ( Pearson et al, 1997 ). Furthermore, colonization, biofilm, and virulence are all linked to motility and are thought to have a role in pathogenesis ( Badal et al, 2021 ). We found a significant reduction in rhamnolipids, as well as swimming and swarming motility, in the presence of BG138 ( Figures 7E,J ).…”

Section: Discussionmentioning

confidence: 99%

A Cyclic Disulfide Diastereomer From Bioactive Fraction of Bruguiera gymnorhiza Shows Anti–Pseudomonas aeruginosa Activity

2022

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Pseudomonas aeruginosa is an opportunistic pathogen that commonly causes hospital-acquired infection and is of great concern in immunocompromised patients. The quorum sensing (QS) mechanism of P. aeruginosa is well studied and known to be responsible for pathogenicity and virulence. The QS inhibitor derived from the natural product can be an important therapeutic agent for pathogen control. The present study reports the role of Bruguiera gymnorhiza purified fraction (BG138) in inhibiting virulence factor production, biofilm formation, quorum sensing molecules, and expression of QS-related genes of P. aeruginosa. Structural characterization of BG138 by high resolution mass spectrometry, Fourier transform infrared spectroscopy, 1D (1H and 13C NMR) and 2D NMR reveals that the fraction is a mixture of already known cyclic disulfide diastereomer, namely, brugierol and isobrugierol. The minimum inhibitory concentration (MIC) of BG138 against P. aeruginosa was 32 μg/ml. Biofilm formation was significantly reduced at sub-MIC concentrations of BG138. Scanning electron microscopy analysis reports the concentration-dependent biofilm inhibition and morphological changes of P. aeruginosa. Flow cytometry–based cell viability assay showed that P. aeruginosa cells exhibit increased propidium iodide uptake on treatment with 32 and 64 μg/ml of BG138. At sub-MIC concentrations, BG138 exhibited significant inhibition of virulence factors and reduced swimming and swarming motility of P. aeruginosa. Furthermore, the effect of BG138 on the expression of QS-related genes was investigated by qRT-PCR. Taken together, our study reports the isolation and structural characterization of bioactive fraction BG138 from B. gymnorhiza and its anti-biofilm, anti-virulence, anti-quorum sensing, and cell-damaging activities against P. aeruginosa.

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Foraging Signals Promote Swarming in Starving Pseudomonas aeruginosa

Abstract: P. aeruginosa , a Gram-negative opportunistic pathogen, can adapt to diverse ecological niches and exhibits several forms of social behavior. Swarming (flagellum-driven collective motility) is a collective behavior of P. aeruginosa exclusively over semisolid surfaces.

Cited by 22 publications

References 49 publications

Toroidal displacement of Klebsiella pneumoniae by Pseudomonas aeruginosa is a unique mechanism to avoid competition for iron

Toroidal displacement of Klebsiella pneumoniae by Pseudomonas aeruginosa is a unique mechanism to avoid competition for iron

Systems-wide dissection of organic acid assimilation in Pseudomonas aeruginosa reveals a novel path to underground metabolism

A Cyclic Disulfide Diastereomer From Bioactive Fraction of Bruguiera gymnorhiza Shows Anti–Pseudomonas aeruginosa Activity

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